In the field of lighting, present developments aim to reduce the power consumption used for everyday lighting. For general room lighting applications, such as in residential or commercial environments, light emitting diodes (LEDs) already have become an alternative to conventional incandescent or halogen lamps. In addition to a reduced power consumption, LEDs provide the further advantage of a dramatically increased lifetime, which reduces the cost of installation and replacement.
When employing light sources comprising LEDs or similar devices, it is typically necessary to provide a constant current to the one or more LEDs since the current through an LED varies exponentially with the applied voltage. Without suitable circuitry, a variation in the voltage may easily cause overcurrent and thus damage to the LED. Accordingly, driver circuits are known in the art, limiting the current when driving an LED with a voltage source such as mains.
A general problem when using LEDs in light sources for illumination purposes, such as room lighting applications, is that the light output needs to be substantially flicker-free to provide a user, e.g. in an office environment, with a suitable work light of constant brightness. Elaborate circuit designs exist in the art, e.g. using switching mode power supplies, which allow to provide the LEDs with a correspondingly constant current, even under difficult operating conditions, such as variations in the voltage, provided by the voltage source.
However, presently available solutions typically comprise complex and thus costly circuitry, which is unsuitable for mass-market applications.
In view of the above, it is an object of the present invention to provide a versatile driver circuit for at least a load, such as a LED unit, which is cost-efficient while simultaneously providing high-quality and substantially flicker-free light output.